Right angles


Within our daily life we come across geometric shapes , squares, circles, triangles and other shapes that make up everything around us. Although we cannot discern it because we are used to seeing this represented in notebooks and books and not reflected in our daily lives, just by watching TV which is a rectangle or our mobile phones which is usually also a rectangle we can see it. All these geometric shapes are created from straight lines and angles, both flat and straight and varied to shape its image, such as an Apple mobile phone whose equipment has a rectangular shape (has 4 right angles and 2 flat angles ).


What are right angles?

The simplest way to understand what right angles are is to see them as the space that exists between two lines which share the same vertex and giving a total opening in degrees of 90º. The word angle etymologically speaking comes from the Greek ” ankulus ” which can be translated as bent or twisted. With the passage of time it was transferred to Latin where it was established as ” angulus ” which can be understood to be translated as angle.

  • Definition
  • Characteristics of right angles
  • How much is a right angle and how is it measured?
  • Parts of right angles
  • Types of angles
  • Right angle triangle


The right angle is defined as a line with an opening of 90 degrees, that is, sexagesimal. Within its amplitude of measurement it is also established in other units such as π / 2 radians and also 100 g  centesimals.


It is Euclid who gives the definition of “It is an angle that occurs when a straight line that is presented on another ends up producing an alignment between it, generating a totally adjacent angle making its angle is right and that the line that is on she is a perpendicular line ”.

Characteristics of right angles

  • Right angles allow us to combine to create other kinds of angles. If, for example, two right angles are connected on a plane we will see between them the formation of another called flat angle, while if we form 4 right angles on a plane we will get another angle called perigonal which makes up 360 degrees .
  • When we look at a square we can see that it is made up of four equal and totally parallel sides , we can understand that each of its interior angles are right, that is, 90 degrees and when all the angles are added, it gives n the total metric measurement of the degrees that is 360 degrees.
  • As is logical, right angles must never vary, and it is considered that of all the existing angles this is the easiest to recognize compared to the other types.

How much is a right angle and how is it measured?

Before knowing how much a right angle measures, we must know how angles are measured and for this we must use a protractor. The protractor is a tool widely used in engineering and architecture which allows to know the degrees of opening or elevation of a point.

The conveyor has a circle shape separated by half which is the most common because there are other models that form a complete circumference.

It has a base where the center point is established, which is aligned with the 0 degree point and all the degrees from 0 to 180 degrees are found throughout the arc of the circumference .

To know how much a right angle measures and how it is measured , the protractor is taken and placed at the vertex point , it is observed where the line projected on this vertex is and the number of degrees it has is determined. The to angles straight have an opening 90 degrees would be reflected in this way:

Parts of right angles

For an angle to be called an angle, it must comply with all the parts that make it up. These are:

  • A vertex or opening point.
  • Two or more lines or vectors that are connected at a specific point.

Types of angles

Apart from the right angle there are several types of angles that we will see below:

  • Acute angles: Are those that start from 0 degrees to ninety degrees so they cannot exceed a quarter turn.
  • Obtuse angle: which measures more than 90 degrees but cannot exceed 180 degrees, that is, it is equivalent to a rotation greater than a quarter of a turn but less than a half turn.
  • Plain angle: It is one that measures exactly 180 degrees, which would be equivalent to half a turn. This will always be recognized as a long straight line opposite its point of origin.
  • Concave angle: They are those that measure more than 180 degrees, that is, more than half a turn.
  • Whole or complete angles: They are those that measure exactly 360 degrees, that is, a whole turn.

Right angle triangle

Within the right angles we see different geometric shapes that have remaining angles including squares and rectangles, there is also a triangle called a right triangle which has an angle of 90 degrees.

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